1. Field of the Invention
This invention relates to catalyst compositions and a process for preparing such compositions. More particularly, this invention relates to catalyst compositions comprising the adduct of:
(a) an alumina-silica-metal oxide combination represented by the formula: EQU (Al.sub.2 O.sub.3).sub.a (SiO.sub.2).sub.b (M.sub.2/n O).sub.c
wherein M is a metal cation selected from the group consisting of the lanthanides or rare earths, Groups 1b, 2b, 5b, 6b, 7b, and 8 of the Periodic Table of the Elements, and mixtures thereof, and a, b, and c represent weight percent of the Al.sub.2 O.sub.3, SiO.sub.2, and M.sub.2/n O components, respectively, in the alumina-silica-metal oxide combination, with a being 0 to 100, b being 0 to 100, and c being 0 to 50 and n represents an integer from 1 to 7 of the valence of the metal cation, with the proviso that the sum of (a+b) must be greater than 0, and
(b) a catalytically effective amount of sulfur trioxide.
The catalyst compositions of this invention may be used for any of a wide variety of purposes generally known in the art. Thus, for example, the compositions are useful as catalysts in the transformation of numerous organic compounds in the vapor phase such as alkylation and/or nitration of aromatic compounds, dehydrogenation reactions, oxidation reactions, hydrogenation reactions, skeletal isomerization reactions, and the like. The catalyst compositions may be employed in a manner identical to that for catalysts heretofore known in the art for such transformations.
2. Description of the Prior Art
Various vapor phase processes which employ numerous catalyst compositions are known for the transformation of organic compounds. Thus, the vapor phase nitration of benzene and toluene in the present of silica gel at temperatures ranging from about 275.degree. C. to about 310.degree. C. is described in McKee and Wilhelm, Industrial and Engineering Chemistry, 28(6), 662-667 (1936) and U.S. Pat. No. 2,109,873. Bauxite and alumina were reported to be ineffective as catalysts in the vapor phase nitration of benzene.
U.S. Pat. No. 4,107,220 discloses the use of molecular sieves (aluminosilicates) having a pore size varying from about 5 A to about 10 A as catalysts to control the para-to-ortho isomer distribution of nitrochlorobenzene in the vapor phase nitration of chlorobenzene. Suitable temperatures are reported to range from about 190.degree. C. to about 290.degree. C.
The use of silver-containing catalysts in processes for the direct oxidation of ethylene to ethylene oxide is disclosed in numerous patents, for example, U.S. Pat. Nos. 3,962,136, 3,793,231, 2,831,870 to cite just a few.
Crystalline alumina silicate is reported in Harper et al, "Alkylation of Benzene with Propylene over a Crystalline Alumina Silicate," ACS Symposium on Recent Advances in Alkylation Chemistry, New Orleans, LA, Mar. 20-25 (1979) to be an effective catalyst in the alkylation of benzene with propylene to produce cumene and minor amounts of poly-isopropylbenzenes.
The vapor phase Friedel-Crafts alkylation of toluene and phenol with alkyl chloroformates and alkyl oxalates in the presence of a solid superacid, perfluorinated resinsulfonic acid, known as Nafion.RTM. -H, as catalyst is described in Olah et al, Journal of Catalysis, 61(1), 96-102 (1980). Such solid acids are designated as solid superacids due to their high acid strength, that is, having an acid strength stronger than 100 percent sulfuric acid. Similar alkylations of benzene with ethylene and propylene are disclosed in Olah et al, Journal of Organic Chemistry, 42(26), 4187-4191 (1977).
Solid superacids also are disclosed as effective to catalyze the skeletal isomerization of butane to isobutane and minor amounts of by-products. Among the solid superacids disclosed are zirconia/sulfate ion [Hino et al, JCS Chemical Communications, 851-852 (1980)], titania/sulfate ion [Idem, ibid 1148-1149 (1979)], iron (III) oxide/sulfate ion [Hino et al, Chemistry Letters (Japan) 1259-1260 (1979)], and SbF.sub.5 --TiO.sub.2 --SiO.sub.2, SbF.sub.5 --TiO.sub.2, and SbF.sub.5 --SiO.sub.2 --Al.sub.2 O.sub.3 [Tanabe et al, Chemistry Letters (Japan), 625-626 (1979)].
Although these prior art catalysts are effective to provide the desired product, the commercial utility of a catalyst system is highly dependent upon the cost of the system, the conversion of the reactant(s) and the yield of the desired product(s). In many cases, a reduction in the cost of a catalyst system on the order of a few cents per pound or a small percent increase in the yield of the desired product represents a tremendous commercial economical savings. Accordingly, research efforts are continually being made to define new or improved catalyst systems and methods and processes of making new and old catalyst systems to reduce the cost and/or upgrade the activity and selectivity of such catalyst systems in particular processes. The discovery of the catalyst compositions of the present invention, therefore, is believed to be a decided advance in the catalyst art.